Field
The disclosed concept pertains generally to power distribution and, more particularly, to high voltage direct current transmission and distribution systems, such as, for example, such systems for above ground, below ground or subsea applications. The disclosed concept further pertains to circuit interrupters for high voltage direct current distribution systems.
Background Information
Alternating current (AC) power distribution systems are well known.
High voltage, direct current (DC) power distribution systems have less energy losses and require less costly transmission cables than corresponding AC distribution systems. In long transmission lines and, in particular, in ones that use cable, high voltage DC power transmission may be the only feasible method of power transmission because using AC will cause debilitating instability and excessive losses.
When connecting a DC voltage source to a relatively long cable transmission line when the cable capacitance is discharged, relatively large oscillatory currents occur which, in turn, generate relatively large voltage spikes along the cable length. These voltage spikes can compromise the insulation of the cable itself as well as the insulation of any device electrically connected thereto.
Furthermore, the relatively large oscillatory currents can cause nuisance tripping of protection devices of the transmission line.
There is room for improvement in high voltage direct current transmission and distribution systems specifically regarding, for example, the cable charging process when the transmission line is energized.
There is also room for improvement in circuit interrupters for such systems.